Packaging method and apparatus



Sept. 16, 1969 p, SORENSEN ET AL 3,466,838

PACKAGING METHOD AND APPARATUS Filed Dec. 30, 1966 s Sheets-Shet 1 7 74,'Yg W+p-eert Se t. 16, 1969 R. P. SORENSEN ET AL 3,466,838

PACKAGING METHOD AND APPARATUS 5 Sheets-Sheet 2 Filed Dec. 30, 1966Sept. 16, 1969 R. P. SORENSEN ET AL 3,466,838

PACKAGING METHOD AND APPARATUS Filed Dec. 30, 1966' 5 Sheets$heet 5United States Patent US. C]. 53-29 11 Claims ABSTRACT OF THE DISCLOSUREA method of packaging ice cream in cartons including: directing jets ofhot air against the outside of folded end flaps of a filled carton atlocations overlying areas of heat scalable adhesive on the underside ofthe flaps, and cooling the end flaps. An apparatus for sealing thefolded end flaps of a carton including a distributor head spaced fromthe end flaps and for directing continuously flowing hot air against theouter surface of the end flaps to soften adhesive carried on theunderside of the flaps, a heater head for heating the air, a conveyorfor moving the cartons to the distributor head in step fashion, and acooling head thereafter contacting the end flaps.

Background of the invention This invention relates to improvements inpackaging methods and apparatus.

The present invention is particularly advantageous for packaging incartons of the type having end flaps for folding in overlappingrelationship and having a heat scalable material disposed inwardly ofthe outer surface of the end flaps. Such cartons are well known, beingfrequently used in packaging ice cream, for example. A typical carton isdisclosed in US. Patent No. 3,219,257 issued to Ralph F. Anderson.Cartons of this type are commonly preformed and fed to a packagingmachine in flattened condition. The machine then opens the carton, foldsthe lower flaps, fills the carton through the open upper end, and thenfolds the upper end flaps. Heretofore the adhesive has sometimes beensoftened prior to infolding of the end flaps. This is diflicult toaccomplish. Another practice is to fold the end flaps and then applyheat to the entire end of the carton, as with a hot blade, to soften theadhesive and seal the carton. With some products, such as frozencomestibles, it is diflicult to apply adequate heat to the folded endflaps of a carton to seal the same, without also adverse- 1y affectingthe product in the carton. When contact-type heat sealers are used, itis difficult to maintain temperature control within proper limits. Also,waxes and other thermoplastic materials on the outer surface of thecartons will adhere to a contact-type heat sealer, further aggravatingthe temperature control problem and necessitating cleaning.

Summary The present invention provides a new and useful method ofpackaging a frozen comestible and an improved sealing apparatus whichmay include a unique heater apparatus.

It is a general object of the present invention to provide a new anduseful packaging method and apparatus which alleviates the above notedproblems.

Another object is to provide a packaging apparatus and method forsealing cartons after the end flaps have been folded in overlappingrelationship.

Still another object is to provide a new and useful heater apparatus anda distributor means usable therewith.

The above, as well as other advantages and objects of the presentinvention, will become apparent as the same 3,466,838 Patented Sept. 16,1969 ice.

becomes better understood from the following detailed description whentaken in conjunction with the drawings.

Drawings FIGURE 1 is a front elevational view of a packaging machineincorporating a preferred embodiment of the present invention andcapable of performing the steps of the method;

FIG. 2 is a perspective view of one type of carton which may be sealedby the method and apparatus of this invention;

FIG. 3 is a generally diagrammatic, perspective view of a portion of theapparatus of FIG. 1;

FIG. 4 is a plan view of a preferred embodiment of the improved portionof the apparatus of FIG. 1;

FIG. 5 is a front elevational view as taken along line 5-5 of FIG. 4;

FIG. 6 is a partial cross-sectional view taken generally along line 66of FIG. 5;

FIG. 7 is a view taken along line 77 of FIG. 5; and

FIG. 8 is a sectional view, on a larger scale, taken along line 8-8 ofFIG. 7.

Description The preferred embodiment hereafter described includes amachine for erecting cartons, folding the end flaps thereof, and fillingthe cartons. The machine advantageously has mechanism for advancing thecartons in step fashion. The preferred embodiment includes a sealingapparatus S, including a heating station, whereat adhesive on the cartonflaps is softened, and a cooling station where the adhesive is hardenedto complete the seal.

Reference is now made more particularly to the drawings which illustratethe best presently known mode of carrying out the invention and whereinsimilar reference characters indicate the same parts throughout theseveral views.

A typical carton C, best illustrated in FIG. 2, may be formed from ablank conveniently of cardboard or the like. The carton illustrated hasits end flaps deflected outwardly for better illustration, it beingunderstood that the end flaps are generally planar with the side wallswhen the carton is first erected. The carton generally includes firstand second opposed side walls. 10 and 11, and third and fourth opposedsides walls 13 an 14, each connected along fold lines to one edge ofeach of the first and second side walls. The side walls each have endflaps connected to opposite ends along fold lines, and the end flaps arearranged for folding in overlapping relationship, as shown in FIG. 3.Side wall 14 has end flaps 14a, 14b shaped for generally overlying theupper and lower ends of the carton, respectively. At the upper end ofthe carton, side walls 11, 10 and 13, have upper end flaps 11a, 10a and13a adapted for infolding in that order after end flap 14a has firstbeen folded. Similarly, lower end flaps 11b, 10b and 13b are arrangedfor infolding in overlying relationship. An adhesive is applied to anadhesive area 16 on the underside of end flap 13a. An adhesive is alsoapplied to a second adhesive area 17 on the underside of end flap 10a.In a similar fashion, adhesive areas are located on the bottom end flapsas shown at 16 and 17', these areas being a mirror image of thepreviously described areas 16 and 17. The adhesive on areas 16, 17, 16and 17' is preferably of the heat-sensitive type which isheat-softenable and which will harden rapidly upon cooling. In thismanner, when the end flaps are folded in overlapping relationship, asshown in FIG. 3, the heatsealable adhesive is in a pattern on selectedareas of the overlapping surfaces of the flaps and disposed inwardly ofthe exposed outer surface of the flaps. It is contemplated that theadhesive may be otherwise located than on the underside of the flaps,such as on the outer side of the overlapped area; however, theabove-described arrangement is preferred. It should be understood thatthe above-described carton is merely typical of cartons usable in thepresent invention and that the invention should not be limited to theexact carton described. Another typical carton is described in detail inthe aforementioned patent to Ralph F. Anderson, and reference is madethereto for more complete description of the structure of such a carton.

The sealing apparatus S of the present invention is specificallydesigned for use with a carton erecting, filling and closing machine ofthe type shown in United States Patent No. 2,612,016, issued to Swan F.Anderson, and is herein described in conjunction with such a packagingmachine. It is to be understood, however, that the sealing apparatus canbe adapted for use with other packaging machines and that certainfeatures of the present invention are of general utility.

The carton filling and closing machine illustrated in FIG. 1 is morespecifically disclosed in the aforementioned Patent No. 2,612,016, andreference is hereby made to that patent for a more complete descriptionof the construction and operation of the filling machine. In general,the machine includes a base 21, a carton feeding and erecting apparatus22, a lower flap-folding apparatus 23, a filling mechanism 24, an uppercarton flap-folding mechanism 25, and a conveyor means 26 forintermittently advancing the cartons in step fashion from the feedingand erecting mechanism 22 past the folding and filling apparatus. Thesealing apparatus S is provided at the discharge end of the conveyor 26,it being understood that the invention is not limited to this exactlocation.

The conveyor 26 includes laterally spaced pairs of upper and lower rails31 and 32 which form guideways therebetween for slidably supporting anelongated slide member. In the embodiment illustrated, the slide membershave a plurality of sets of carton-engaging pawls. 33a-33f at spacedpoints therealong, and which carton-engaging pawls project into thespace between the slides to engage the cartons therebetween and index oradvance the cartons in step fashion when the slide members moveforwardly (to the left as viewed in FIG. 1). The pawls are shaped so asto automatically retract when the slide members move rearwardly to passaround the cartons and behind the next proceeding carton. The slidemember is reciprocated by a drive mechanism generally designated 35,which includes a motor 36 drivingly connected to a onerevolution clutch37. The one-revolution clutch is connected to an eccentric 38 which isdriven through one revolution each time the clutch is operated. Theeccentric 38 is connected through a link 41 to a lever 42 pivotallyattached as at 43, to the base 21. Lever 42 has its upper end connectedthrough linkage 44 and 45 to extend and retract the slide member.

The sealing apparatus, generally designated S, is provided at thedischarge end of conveyor 26 and is mounted on the filling machine inany suitable manner. As shown, the mounting includes a bracket support48 attached to the base 21, and longitudinal supports 49 and 50, bestshown in FIG. 4. In general, the sealing apparatus S may include upperand lower fingers 51 and 52, upper and lower distributor heads 54 and55, upper and lower heating mechanisms 56 and 57, a supply of air underpressure 59, upper and lower cooling heads 61 and 62, a chiller 63, aconveyor mechanism 64, and a drive mechanism 65.

Bracket 48 provides support for a framework including a vertical supportmember 71 attached to longitudinal support member 49 upon which aremounted transverse frame members 73 and 74 and a vertical mountingbracket 75. Cooling heads, generally designated 61 and 62, are securedto the upper and lower legs, respectively, of transverse frame members73 and 74 in any convenient manner, as by bolting. As best shown in FIG.6, upper cooling head 61 is advantageously formed of a plurality ofrectangular tubular members 61a-61c in side-by-side parallelrelationship and advantageously having a width to accommodate the widthof carton C. The tubular members are provided with end closures 77 and78 and with internal openings, as at 76, to communicate the tubularmembers to provide a continuous channel for flow of a coolanttherethrough. For this purpose, an inlet 79 is provided in tubularmember 61c, and an outlet 80 is provided in tubular member 61a. Lowercooling head 62 is similarly constructed and has end closures 7'7 and78, an inlet 79', and an outlet 80', as best shown in FIG. 5. Inlets '79and 79 are connected to chiller 63 by conduit 81 (see FIG. 1), and thechiller conveniently includes means for pumping the coolant through theconduit and cooling heads. Outlets 80 and 80 are likewise connected to areturn conduit 82 to return the liquid to the chiller 63 which isarranged to cool the liquid sufficiently for recirculation to thecooling heads. Chiller 63 is conveniently connected to any convenientsource of supply as by conduit 83 and, in the embodiment illusrated,water is conveniently used as the coolant liquid. It should beunderstood that the number of tubular members in each head is notimportant, and that they need not be contiguous in all cases.Preferably, however, the cooling heads 61 and 62 are spaced from eachother a dimension corresponding to the height of container C so that theheads serve to maintain the folded flaps contiguous during the coolingoperation, at which time the adhesive hardens and completes the seal.For this purpose, upper cooling head 61 is conveniently adjustable, asshown in FIGS. 4-6. Adjustable bolts 66 and 67 are threaded through theupper leg of frame members 73 and 74, respectively. Each bolt isconveniently provided with a lock nut and operates to position coolinghead 61. A pair of bolts 68 and 69 are secured to members 61c and 61a,respectively, and pass through openings in the frame 74. Springs 68a and69a urge the cooling head 61 upwardly against bolt 67. A similararrangement is provided to urge the other end of cooling head 61 againstbolt 66. It should be noted that upper and lower end closures 78 and78', respectively, have outwardly extending tapered portions to aid inthe receipt of the container between the cooling heads.

Conveyor 64 is arranged for advancing the cartons through the coolingheads. In the embodiment illustrated, the conveyor includes a pair ofbelt-type mechanisms adjacent each side of the cooling heads forengaging the adjacent sides of the carton C and advancing the cartons.The front pair of belt-type mechanism includes upper pulleys 86 and 87mounted on the upper legs of frames 73 and 74, respectively, and lowerpulleys 88 and 89 mounted on the lower legs of frames 73 and 74,respectively. Upper and lower belts 91 and 92 extend between the upperand lower pairs of pulleys. Pulleys 86 and 88 are interconnected bydrive shaft 94 which depends below the lower leg of frame 73 and has asprocket 95 attached thereto (see FIG. 5). The other pair of belttypemechanism is similarly arranged, and similar parts are designated in thedrawing by the same numerals with the postscript prime and furtherdescription is deemed unnecessary. The conveyor is driven by drivemechanism 65 which includes a motor 96 mounted on vertical supportmember 71 as by bracket 97 and arranged for driving sprocket 98. A chain99 is entrained around sprockets 95, 95' and an idler sprocket 101 insuch a manner that sprockets 95 and 95' are driven in oppositedirections, as shown in FIG. 4. In this manner, the opposite pairs ofbelt-type mechanism are driven in opposite directions and cooperate toadvance the containers. The conveyor mechanism 64 is advantageouslyarranged to advance the cartons at a speed greater than the maximumspeed of the machine. In this manner, the speed of the conveyor 64 neednot be adjusted with adjustments in the rate of cartons filled by themachine. It is contemplated that other arrangements may be utilized topass the containers between the cooling heads, if desired.

Fingers 51 and 52 are conveniently mounted on end closures 78 and 78',respectively, and extend longitudinally toward the filling machine, asbest seen in FIG. 5. The fingers hold the folded flaps contiguous infolded position, and cooperate with the pairs of spaced rails 31 and 32(see FIG. 4) to support the filled cartons at the heating station. Theouter ends 51a and 52a (see FIG. 1 of the fingers 51 and 52 areadvantageously bent away from the carton to allow the carton to easilyslide between the fingers. As best seen in FIG. 7, the fingers areoffset somewhat from the center line so as to not interfere with airdischarged from the distributor head 54 and 55, as will hereinafterbecome apparent. It should be understood that the exact location of thefingers may be varied in accordance with the glue pattern on that othermeans for holding the flap contiguous may be utilized, if desired.

At the heating station are located tubular distributor heads 54 and 55and heating heads 56 and 57. As best shown in FIG. 7, heating head 56 ismounted on vertical mounting bracket 75 by means of parallel links 102and 103. Similarly, heater head 57 is mounted by parallel links 104 and105. Links 103 and 104 are interconnected by arm 106, and link 103extends outwardly a convenient distance to provide a handle which may bemoved between the positions shown in solid and in phantom in FIG. 7. Inthis manner, all links 102-105 are moved simultaneously and heater heads56 and 57 and the attached distributor heads 54 and 55 can be moved fromthe illustrated operative position spaced from the end flaps to aninoperative position spaced further therefrom. An eccentric 107 ismounted on link 102 and engages a stop 108 on bracket 75 to limitmovement at the operative position. Eccentric 107 is provided with aplurality of positions so that the distance distributor heads 54 and 55are disposed from the carton C may be selectively adjusted. The distanceof the distributor heads can be selected empirically and will depend onvarious variants including thickness of the carton flaps, speed of themachine, air pressure, air temperature, and type of adhesive used. Ithas been found that an eccentric arrangement to provide a distributorhead spacing from one-quarter to one-half inch will accommodate mostsituations. A second stop 109 is conveniently mounted on link 103 forengaging bracket 75 to limit movement at the inoperative position.

Heater heads 56 and 57 are of identical construction, and the followingdescription of heater head 56 should be taken as applying also to heaterhead 57. As best shown in FIG. 8, heater head 56 comprises an elongatecylindrical housing 111 having end portions 112 and 113 secured thereto.End portion 112 has an outlet opening 114 centered therein. rAn inletopening in the form of orifice 115 is located in housing 111 adjacentthe end portion 113. A generally cylindrical heating element 118 iscoaxially disposed in housing 111 and extends to a point adjacent outletopening 114. Heating element 118 is preferably attached to end portion113 and has its electrical conductors extending through the end portion113. The conductors advantageously terminate in prongs 121 and 122 whichmay be connected to a power source as through cable 123. A sleeve 124 isattached to end portion 112 and surrounds heating element 118. Thesleeve 124 conveniently extends the majority of the length of theheating element and is spaced therefrom to accommodate a helical wrap125 therebetween. Helical wrap 125 defines a continuous path aroundheating element 118 for the passage of air from inlet 115 to outlet 114.In the embodiment illustrated, helical wrap 125 is advantageously in theform of a stainless steel spring closely adjacent both the heatingelement 118 and sleeve 124. A wall 126 engages both housing 111 andsleeve 124 to define an inlet chamber 127 into which inlet opening 115communicates. Disposed between sleeve 124 and housing 111 is insulationherein shown as tubing 128 advantageously formed of mica and havingreflective qualities. lAs can be seen, the mica tube 128 extends fromend portion 112 to wall 126.

As stated above, heating element 118 is preferably attached to endportion 113 and extends to a point adjacent end portion 112. It has beenfound that heating element 118 preferably has a higher heating capacityadjacent end portion 113 than adjacent outlet 114. In this embodiment, aheating capacity of 1000 watts is utilized for the higher heatingcapacity and 600 watts is utilized adjacent outlet 114. This may beachieved in any convenient manner such as by providing additionalwinding for the higher heating capacity. In this manner, heating element118 provides its higher capacity at a point adjacent inlet where coolair enters chamber 127. As this air passes along the path defined byspiral wrap 125, a certain amount of heat is carried along the heaterelement. As a result, this cooperates with the lower heatinfi capacityto maintain a substantially uniform temperature throughout the fulllength of the heating element 118 and thereby maintain a longer life ofthe heating element. Additionally, this provides a substantially uniformheating of the air discharged through outlet 114. With a high heatingcapacity adjacent inlet 115, it is preferable that no electricalconnections be exposed inside the heating head. As a result, it ispreferable that the conductors extend through end portion 113 asdescribed above. With the exception of the mica insulation 128, theparts of heater head 56 advantageously have a stainless steel exteriorfor resistance to corrosion, and for sanitary purposes when used inpackaging comestibles.

Inlet opening 115 communicates with conduit 131 which is attached toconduit 132 leading from air supply 59. Interposed in conduit 132 is apressure regulator 133. It has been found that by using an orifice 115of 0.116" diameter, the pressure in chamber 127 is about one-fifth ofthe pressure in conduits 131 and 132, when the conduit pressure is about20-30 p.s.i. Thus, if regulator 133 is set so that the pressure on gauge134 shows 25 p.s.i., the pressure in the heating head will be one-fifthof that, or five pounds. Since the pressure of the supply 59 willnecessarily vary, this particular arrangement is such that as much astwo and one-half pounds variance in supply pressure, for example, willcause only one-half pound of variance in the heating and distributorhead pressure. This allows a wider range of control by regulator 133 tomaintain the outlet pressure within desirable limits.

Communicating with conduit 132 is a pressure-actuated switch 135 whichoperates as an electrical safety valve. As can be seen, an inlet cable136 which may be attached to any convenient source of supply, leads tosafety valve 135, and cables 123 and 123 lead therefrom. With thisarrangement, when the pressure in conduit 132 varies beyond theallowable limits, the switch 135 is opened. In this manner, the supplyis cut off to the heater heads 56 and 57, thereby terminating theiroperation and providing a convenient safety measure.

Distributor heads 54 and 55 are advantageously mounted on heaterheads 56and 57, respectively. As best shown in FIG. 8, end portion 112conveniently includes a nipple 112a through which outlet 114 passes.Distributor head 54 has a sleeve 141 arranged for surrounding nipple112a. Sleeve 141 is conveniently clamped on nipple 112a as by fastener144. The distributor heads are advantageously shaped complementary tothe pattern of adhesive on the underside of the end flaps of carton C.Since adhesive areas 16 and 17 are generally T-shaped, the distributorheads are similarly shaped. Preferably, the distributor heads arearranged for directing air against two cartons, and thus a doubleT-shape is illustrated. In this manner, the carton designated Ca in FIG.3 has its flaps preheated by the first portion of the distributor headand then advances to the position occupied by carton Ob where theheating continues to soften the adhesive. This arrangement allows forfaster softening of the adhesive at the heating station, but it shouldbe understood that the present invention is not limited to such atwo-step heating. As shown, a plurality of openings 150 are provided ina pattern complementary to the pattern of adhesive on the carton C. Ithas been found that holes 150 should be quite small to provide properdistribution of hot air throughout the distributor head. With a patternof openings as illustrated in FIG. 3, openings 150 having a diameter inthe range of 0.035" to 0.060 are exemplary. In the embodimentillustrated, the openings are preferably 0.052" in diameter and areadvantageously arranged in a generally rectangular pattern fromoneeighth to one-quarter inch on center. The particular patternillustrated in FIG. 3 has been found to accommodate a large number oftypical cartons and thus has a wide range of usability. As stated above,the pattern of the openings is complementary to the pattern of adhesive.By this it is meant that the openings are arranged to direct hot airagainst the majority of the adhesive pattern. It is important, however,that key areas of the adhesive be softened for sealing the flapstogether. Likewise, a few openings outside of the adhesive pattern arenot critical; however, hot air should not be directed against the entireend area of the carton since this could damage the contents. In thepresent embodiment, for example, hot air is directed against about 10%of the end area, thereby assuring no damage to the contents whileeffectuating a good seal of the end flaps.

With the above apparatus, it has been found that sealing of cartons canbe quickly and economically performed. The apparatus is arranged toprovide air preferably at about 5 /2 p.s.i. in the heating head anddischarged at this pressure through openings 150. Heating element 118 isadvantageously arranged to operate at about 1750 F. and, at the abovepressure, will heat the air to about 1350" F. With this arrangement,distributor heads 54 and 55 are disposed from one-quarter to one-halfinch from the end flaps, depending on the speed of the machine whichwill vary the time the carton C is disposed between the distributorheads. Following the softening of the adhesive, the next carton advancedby the filling machine will push carton Ca to position Cb. This causescarton Cb to be pushed to the cooling station where it is advancedbetween the cooling heads by the aforedescribed conveyor mechanism 64 tocool the end flaps and adhesive, and thereby complete the sealingoperation.

The aforedescribed apparatus is capable of performing the method of thepresent invention which relates to packaging a frozen comestible, suchas ice cream, in cartons of the type described. Such cartons have endflaps which are adapted to be folded in overlapping relationship andhave a heat-scalable adhesive in a pattern on selected areas of theoverlapping surfaces of the flaps. The cartons are erected and the endflaps are folded at one end thereof. The carton is then filled with thefrozen comestible through the other end, and the end flaps are folded atsaid other end. Thereafter, a plurality of jets of hot air is directedagainst the outside of the folded flaps at locations overlying saidpreselected adhesive areas to soften the adhesive while the overlappingflaps are held in a contiguous position. Thereafter, the overlying endflaps are cooled to harden the adhesive and complete the seal while theoverlapped flaps are still held contiguous. More particularly, thecartons are indexed or advanced intermittently in a step fashion whereinthe cartons are stopped for a preselected interval during filling of thecarton. The advancement is also stopped while the hot air is directedagainst the outside of the folded flaps for a time interval generallyequal to the time for filling the carton. The hot air is directedthrough a distributing head apparatus spaced from the folded flaps andhaving a plurality of openings generally complementary to the adhesivepattern. As can be seen, the upper and lower flaps are sealed after thefrozen comestible has been placed in the carton. Preferably, first andsecond sets of jets of hot air in said pattern are provided, and theadvancement of the cartons is stopped for said preselected interval ateach said first and second sets of openings to soften the adhesive.

The invention in its broader aspects is not limited to the specificsteps and apparatus shown and described, but departures may be madetherefrom within the scope of the accompanying claims without departingfrom the principles of the invention and without sacrificing its chiefadvantages.

What is claimed is:

1. In a machine for filling and closing cartons of the type having endflaps at the upper and lower ends thereof as it moves through themachine, the flaps at each end movable to an overlapping folded positionand having a heat scalable material in a pattern on preselected areasdisposed inwardly of the exposed outer surface of the flaps in saidfolded position; said machine having conveyor means for advancing thecartons along a path, means for folding the lower flaps, means at afilling station for filling the carton through the open upper endthereof, and means for thereafter folding the upper flaps; theimprovement comprising: means for intermittently operating the conveyormeans for movement of the cartons in step fashion to said fillingstation and thereafter to a heating station, means at the heatingstation for holding the upper flaps contiguous in folded position, adistributor head at the heating station spaced from the folded upperflaps and having a plurality of openings arranged complementary to saidpattern of heat sealable material at the upper end, and means forcontinuously supplying hot air to said distributor head for dischargethrough said openings and against the outside of the folded upper flapsin said pattern to soften the heat sealable material.

2. The combination of claim 1 wherein the distributor head openings arearranged in first and second patterns, each pattern being complementaryto said pattern of heat scalable material, and wherein the conveyormeans and the means for intermittently operating the conveyor meansadvance the carton in step fashion to a position under the first patternof openings and then to a second position under the second pattern ofopenings.

3. The combination of claim 1 including means at the heating station forholding the lower flaps contiguous in folded position, a seconddistributor head at the heating station spaced from the folded lowerflaps and having a plurality of openings arranged complementary to thepattern of heat scalable material at the lower end of the container, andmeans for continuously supplying hot air to said second distributor headfor discharge through the openings and against the outside of the foldedlower flaps in the pattern of heat scalable material at the lower end ofthe container to soften said material.

4. The combination of claim 3 including means for holding the upper andlower flaps in contiguous folded position after the heat scalablematerial has been softened and for cooling said flaps to harden saidmaterial and complete the seal.

5. The combination of claim 4 wherein the last-mentioned means includesupper and lower cooling heads spaced apart a distance approximating theheight of the carton, and including means for conveying the cartonsslidably along the cooling heads with the end flaps engaged thereby.

6. The combination of claim 3 including means for simultaneously movingthe distributor heads further away from the carton to an inoperativeposition such that the continuous supplying of hot air will not affectthe heat scalable material of a carton at the heating station.

7. The combination of claim 6 wherein the last-mentioned means isoperable for simultaneously moving the distributor heads from saidinoperative position to an operative position, and including selectivelyadjustable means for engaging the last-mentioned means and forcontrolling the spacing of the distributor heads from the carton at theoperative position.

8. The combination of claim 1 wherein the means for continuouslysupplying hot air includes an elongate heater head having first andsecond ends and end portions at tached to said ends, said heater headhaving an inlet opening at the first end and an outlet opening at thesecond end, means for supplying air under pressure to the inlet opening,means communicating the outlet opening with the distributor head, acylindrical heating element attached to the first end portion andextending to a point adjacent the outlet opening, said heating elementhaving electrical conductors extending through said first end portionand with no electrical connections exposed inside the heater head, saidheating element having a first portion adjacent the inlet opening and asecond portion adjacentthe outlet opening, said first portion having ahigher heating capacity than the second portion, and means defining apath along the heater element for guiding the air past first the firstportion and then the second portion of the heater element to the outletopening.

9. In a machine for filling and closing cartons having end flaps whichare sealable by the application of hot air, the combination of: anelongate heater head having first and second end portions, an inletopening adjacent the first end portion, and an outlet opening in thesecond end portion; a distributor head communicating with the outletopening for directing hot air at the end flaps; a generally cylindricalelongate heating element in the heater head and having a first endattached to the first end portion of the heater head and extending to asecond end adjacent the outlet, said heating element having a firstportion adjacent the inlet and a second portion adjacent the outlet,said first portion having a higher heating capacity than the secondportion; a sleeve attached to the second end portion of the heater headand surrounding the heating element, said sleeve spaced from the heatingelement and extending a part of the length thereof; means for supplyingair under pressure to said inlet opening; and a helical wrap disposedbetween the heating element and the sleeve to provide a path along theheating element for guiding the air first past the first portion andthen the second portion to the outlet opening.

10. In a packaging apparatus for filling and closing cartons of the typehaving end flaps at the upper and lower ends thereof as it moves throughthe apparatus, the flaps at each end movable to an overlapping foldedposition and having a heat sealable material in a pattern on preselectedareas disposed inwardly of the exposed outer surfaces of the flaps inthe folded position, said pattern representing a minor portion of theend area of the carton; said apparatus having conveyor means foradvancing the cartons along a path, means for folding the lower flaps tothe folded position, a filling station having means for filling thecarton through the open upper end thereof, and means for thereafterfolding the upper flaps; the improvement comprising: a heating stationpositioned after the filling station, means for intermittently operatingthe conveyor means for movement of the cartons in a step fashion to thefilling station and thereafter to the heating station, means at theheating station for holding the upper and lower flaps each contiguous infolded position, an upper distributor head at the heating station andspaced from the folded upper flaps, a lower distributor head at theheating station and spaced from the folded lower flaps, each distributorhead having a plurality of hot air openings overlying at least a majorportion of the pattern of heat sealable material at the respectivecarton end but overlying substantially less than the total area of eachcartno end, means for continuously supplying hot air to the distributorheads for discharge through the openings and against a minor portion ofthe outside of the folded upper and lower flaps but said minor portionoverlying at least a major portion of the pattern of heat sealablematerial to soften the same, and means for thereafter cooling the upperand lower flaps and holding the same in contiguous folded position toharden the material and complete the seal.

11. A method of packaging a frozen comestible in cartons of the typesupplied initially flat, said cartons having end flaps adapted to befolded in overlapping relationship and having a heat sealable adhesivein a pattern on selected areas of the overlapping surfaces of the flapsand representing a minor portion of the end area of the carton, saidmethod including advancing said cartons along a path with the flapsdisposed at the upper and lower ends, erecting the cartons and foldingthe flaps at the lower end, filling the carton with the frozencomestible through the open upper end, and folding the flaps at theupper end, the improvement comprising: holding the upper and lower flapscontiguous in said folded position, directing a plurality of jets of hotair against the upper and lower folded flaps in a pattern generallycomplementary to the adhesive pattern, and cooling the folded flaps toharden the adhesive and complete the seal while continuing to hold theflaps contiguous.

References Cited UNITED STATES PATENTS 2,987,605 6/1961 Brandl 219-303 X3,057,125 10/1962 Jensen et al 53-39 X 3,114,226 12/1963 Taggart et a153-375 3,248,843 5/1966 Winters et al 53-39 3,249,024 5/1966 Shiu156-497 X 3,340,777 9/ 1967 Hittenberger et al. 53-375 X FOREIGN PATENTS993,320 5/ 1965 Great Britain.

THERON E. CONDON, Primary Examiner R. I. SPRUILL, Assistant Examiner US.Cl. X.R.

